Left ventricular hypertrophy and ambulatory blood pressure monitoring in chronic renal failure

BACKGROUND: Left ventricular hypertrophy (LVH) is both common and animportant predictor of risk of death in end-stage renal failure (ESRF). Inmild to moderate chronic renal failure (CRF), the timing of onset of LVHand the factors involved in its initial development have not been fullyelucidated. The present study was undertaken to examine the prevalence andpotential determinants of echocardiographically determined LVH in thisconnection, and to compare 24-h ambulatory blood pressure (BP) recordingswith BP measured at a previous clinic visit. METHODS: From a cohort of 120non-diabetic patients who had been attending a nephrology clinic, 118agreed to participate in the study. Of these we selected for analysis 85stable patients (37 male). Patients with known cardiovascular disease,those with a history of poor compliance with antihypertensive medication,and those in whom such medication had been changed in the previous 3 monthswere excluded. Clinic BP, 24-h ambulatory BP, echocardiography, body massindex (BMI), serum creatinine (SCr), creatinine clearance (CrCl),haemoglobin (Hb), fasting cholesterol (CHOL), triglyceride TRIGL), plasmaglucose, calcium (Ca), phosphate (PO4), alkaline phosphatase (ALK PHOS),parathyroid hormone (PTH) concentrations, and 24-h urinary protein wereassessed in all patients. Seventy-seven per cent were on antihypertensivemedication. RESULTS: LVH was detected in 16% of patients with CrCL > 30ml/min, and 38% of patients with CrCl < 30 ml/min. By stepwiseregression analysis, ambulatory systolic BP (P < 0.0001), male gender (P< 0.0001), BMI (P < 0.0002), and Hb concentration (P < 0.002) werethe only independent determinants of left ventricular (LV) mass. Nocturnalsystolic BP (P < 0.02) was the main determinant of LVH in the group ofpatients with advanced CRF. The correlation between left ventricular massindex (LVMI) and mean 24-h ambulatory systolic BP (r = 0.52, 95% confidenceinterval 0.50-0.54) was statistically significantly stronger than withoutpatient systolic BP (r = 0.25, 95% confidence interval 0.23-0.27). Thesame was true for the correlation between LVMI and mean 24-h ambulatorydiastolic BP (r = 0.42, 95% confidence interval 0.40-0.44), and outpatientdiastolic BP (r = 0.22, 95% confidence interval 0.20-0.24). CONCLUSIONS:Twenty-four hour ambulatory BP recording and echocardiography are requiredfor accurate diagnosis of inadequate BP control and early LVH in patientswith chronic renal impairment, independent determinants of which arehypertension, male sex, BMI, and anaemia.